This Core resource to a program-project is focused on defining inborn protein defects that cause osteochondrodysplasia syndromes. We are determining the protein consequences at the molecular level of mutations in genes that cause defects in cartilage structure. This Protein Biochemistry Core actively collaborates in parallel with all projects by providing analytical data from specialized methods, including protein mass spectrometry, applied to tissue samples, purified proteins and cell-culture products. Both luman material from the International Skeletal Dysplasias Registry and mouse tissue and cellular products rom genetically engineered transgenic strains are being studied. Hypotheses as to the nature and biochemical effects of mutations that cause abnormal skeletal development and adult function are integral to the overall goals and aims of all projects and cores. The focus of the Protein Biochemistry Core is to understand the downstream molecular effects of mutations, both new ones identified by human genetic inkage and mutational analysis, and established mutations still with key questions on their protein pathogenesis and created transgenic defects in mice. An example of the latter is the systemic collagen defect in crtap -/- mice. The clinical significance of core work includes direct benefits to families with the conditions under study through more specific diagnoses. In the long term, through an understanding of the effects of altered gene expression, rational approaches to therapy are possible.